Unless otherwise specified Packeta shipments with Shiptheory will use your default shipping location within Packeta. If you would like to use a different shipping location then you need to enter it's indication in the "Sender Indication" advanced setting of your Packeta integration.

To get your desired sender indication log into the Packeta Dashboard and navigate to User Information > Senders. You will be presented with a list of your senders. Copy the value from the indication column for the sender you wish to use for your Shiptheory shpiments.

Once you have copied the value, go to your Packeta integration settings in Shiptheory, open the advanced settings at the bottom of the page and enter the value you copied from Packeta into the "Sender Indication" field. Once you've done this, hit save and Shiptheory will use the new sender indication in all future requests to Packeta.